The present invention relates to spa heater elements and in particular to a titanium electric spa heater element positioned by a snap ring.
Portable spas often use electric spa heaters. Such heaters include heating elements immersed in a flow of sometimes very corrosive liquids, especially when the high levels of chlorine or other chemicals are used to kill algae in the spa or are present do to errors in adding too much chemicals. Known heater element often include welded on fittings. Unfortunately, welding causes the metal close to the welds to be even more susceptible to corrosion.
One solution to heater element survival in such corrosive environment is to use a heater element with a titanium outer wall. Such titanium outer wall is highly resistant to corrosion, and provides an excellent heater element life. Unfortunately, titanium is expensive to machine, and the advantages of a titanium heater element are somewhat cancelled if machined fittings are used to attach the titanium heater element to a heater housing. Welding (or fusing) on the titanium fittings also may make the heater element more susceptible to corrosion.
U.S. Pat. No. 6,621,985 for “Electric Water Heater,” discloses a water heater with a titanium outer wall and using compression fittings to hold the heater element to the heater housing. While the use of compression fittings is less expensive than machined titanium fittings and welding is avoided, such compression fittings apply an amount of pressure on the titanium outer wall requiring either a thick outer titanium wall, or a second wall under the outer titanium wall to support the outer titanium wall. The '985 patent discloses a second stainless steel wall under the titanium outer wall. Either a thick titanium outer wall, or a double wall, add cost to the heater element.